1. Field of the Invention
The present invention relates to an apparatus and a method of its use for predicting rainfall.snowfall conditions based on weather radar images.
2. Technical Background
Conventionally, rainfall.snowfall forecasting by weather radar has been performed on the basis of sampled radar weather images separated short time intervals, and estimating the future weather image by parallel translation of the changes in the two images. More specifically, the two radar images are analyzed to maximize the correlation coefficient between the two radar images, and future displacements of the weather elements are predicted by applying this value of the positional displacement to the translation of the weather elements in the entire image. The obtained value of the translation is applied to the current weather image up to several hours into the future to forecast the future radar weather images. The following references describe some examples of the conventional technique: Yoshio Asuma, Katsuhiro Kikuchi and Hisashi Kon, "Experiments for a Very-short-range Prediction of Snowfall Using a Simple Weather Radar System, Part 1. -Outline and Possibility-", Geophysical Bulletin of Hokkaido University, Sapporo, Japan, v. 44, October, pp35-51,1984; Yoshio Asuma, Katsuhiro Kikuchi and Hisashi Kon, "Experiments for a Very-short-range Prediction of Snowfall Using a Simple Weather Radar System, Part 2. -Examples of Actual Prediction-", Geophysical Bulletin of Hokkaido University, Sapporo, Japan, v. 44, October, pp53-65, 1984; Yoshio Asuma, Katsuhiro Kikuchi and Hisashi Kon, "A Method for Estimating the Advection Velocity of Radar Echoes Using a Simple Weather Radar System", Geophysical Bulletin of Hokkaido University, Sapporo, Japan, v. 44, October, pp23-34,1984.
However, because the conventional radar-based forecasting apparatus performs parallel translation as described above, the apparatus is unable to correct for the effects arising from the behaviors of the actual clouds, such as loss of image points, generation of new points, rotation of the images, non-uniform flow. To deal with such problems, it is possible to utilize fluid dynamics equations such as Navier-Stokes equation. However, it is rare in practice to be able to measure all the parameters required for solving the equation, and even if it was possible to measure all the required parameters, it is still an extremely time-consuming operation, and this approach is not effective in providing short time-range forecasting, for example, after several hours.